Inspection apparatuses for bottles are used e.g. in beverage bottling lines for detecting damaged or dirty bottles. As is generally, known different circumferential views of the bottle side wall are produced simultaneously in a mirror cabinet and imaged onto juxtaposed areas of an imaging sensor. Such apparatuses are disclosed e.g. in EP 0663069 or in DE 19534347.
It is generally desired to image all the views with the least possible amount of distortion, in identical size and without stray light reflections on the bottle surface in transmitted light.
In order to be able to examine the bottle side wall down to the bottom dome in transmitted light, the position from which the bottle is viewed must, however, be only slightly above the bottom of the bottle. It follows that the perspective in the direction of the bottle will be directed at an oblique angle upwards and, in the case of the demanded focal lengths of the objective lens, this will cause the undesired distorted line effect. The larger the distance between the respective object edge and the middle of the image is, the more disturbing this will be. When a plurality of bottle views is projected onto an image area in juxtaposition, the upper areas of the imaged bottles, especially those in the vicinity of the lateral edge of the image, seem to tilt towards the middle.
From DE 19534347 it is known to arrange deflection mirrors on three-point kinematic mounts and to translate and/or rotate the position of the individual bottle views on the image plane by rotating these mirrors about a horizontal and a vertical axis. Distorted lines can, however, not be corrected in this way.